module key_update(data_o,data_i,round_counter);

output wire[79 : 0] data_o; 
input  wire[79 : 0] data_i; 
input  wire[5 : 0] round_counter;

wire [79:0] s1,s2,s3;  //????                                 

sbox key_update_sbox(.data_o(s2[79:76]),.data_i(s1[79:76])); // ??sbox??

assign s1 = {data_i[18:0],data_i[79:19]};//??61?
assign s2[75:0] = s1[75:0]; // ????????4???s???
assign s3 = {s2[79:20],(s2[19:15])^(round_counter),s2[14:0]}; //?k19k18k17k16k15??????????? 
assign data_o = s3;//????

endmodule
